Silver halide emulsion containing acetylene dicarboxylic acid anions antifoggant

ABSTRACT

PHOTOGRAPHIC MATERIALS COMPRISING A LIGHT-SENSITIVE SILVER HALIDE EMULSION LAYER HAVING IN THE EMULSION LAYER OF IN AN ADJACENT WATER-PERMEABLE LAYER A COMPOUND PROVIDING ACETYLENE DICARBOXYLIC ACID ANIONS ARE DESCRIBED. THESE PHOTOGRAPHIC MATERIALS HAVE DECREASED FOGGING TENDENCY, EVEN UNDER CONDITIONS OF HIGH TEMPERATURE AND HUMIDITY, AND THEIR SENSITIVITY IS PRACTICALLY NOT LOWERED BY THE PRESENCE OF THIS COMPOUND.

United States. Patent Office 3,679,423 Patented July 25, 1972 3,679,423 SILVER HALIDE EMULSION CONTAINING ACETYLENE DICARBOXYLIC ACID ANIONS ANTIFOGGANT Robert Joseph Pollet, Vremde, and Autoon Leon Vandenberghe, Hove, Belgium, assignors to Gevaert-Agfa N.V., Mortsel, Belgium No Drawing. Filed June 22, 1970, Scr. No. 48,541 Claims priority, application Great Britain, July 8, 1969, 34,432/ 69 Int. Cl. G03c 5/30 US. Cl. 96-109 8 Claims ABSTRACT OF THE DISCLOSURE Photographic materials comprising a light-sensitive silver halide emulsion layer having in the emulsion layer or in an adjacent water-permeable layer a compound providing acetylene dicarboxylic acid anions are described. These photographic materials have decreased fogging tendency, even under conditions of high temperature and humidity, and their sensitivity is practically not lowered by the presence of this compound.

This invention relates to the stabilization of photographic materials comprising light-sensitive silver halide emulsions, especially to the reduction of fog formation in photographic materials without giving rise to a noteworthy desensitization.

It is well known that light-sensitive silver halide materials comprising gelation silver halide emulsions layers are subject to fogging. Fogging in general and chemical fogging in particular may be defined as the formation of a uniform deposit of silver on development which is dependent on a whole series of circumstances and factors namely on the nature of the emulsions, on their age, on the conditions under which they have been stored, on the development conditions, etc. For particular development conditions the fog tends to be greater if the time of storage and the temperaure and relative humidity of the atmos phere in which the emulsions are stored are increased.

Addenda to the photographic material known as stabilizers or antifoggants protect the light-sensitive silver halide emulsions against formation and growth of fog particularly in high sensitive emulsions and in emulsions which are to be stored under conditions of high temperature and humidity as is for instance the case in tropical countries.

It has now been found that compounds providing acetylene dicarboxylic acid anions have a favourable antifogging action on light-sensitive silver halide emulsions without causing an objectionable desensitization of the lightsensitive material. These compounds include acetylene dicarboxylic acid itself, as well as easily dissociating derivatives of acetylene dicarboxylic acid e.g. a monoor dialkali metal salt, a monoor di-ammonium salt, a monoor di-organic ammonium salt for example mono-anilinium salt, dianilinium salt, di-m-chloroanilinium salt, di-p-methoxyanilinium salt, di-p-toluidinium salt, di-mand p-sulphoanilinium salt, di(diethylammonium) salt, di(triethylammonium)salt, dipyridinium salt, etc., and monoor diesters of acetylene dicarboxylic acid provided they are easily dissociating and thus can provide acetylene dicarboxylic acid anions such as the dibenzohydryl ester.

The antifoggants or stabilizers of use according to the present invention are generally incorporated into the silver halide emulsion layer of the light-sensitive material. The way in which the compounds of use according to the invention are added to emulsions is not critical and the addition can be made during any step of emulsion preparation; they can be added before or after the emulsion has been optically sensitized, preferably just before coating of the emulsion on a suitable support such as for example paper, glass or film.

Instead of incorporating the compounds of the invention into the emulsion layer they can also be incorporated into another layer of the photographic material, e.g. a gelatin antistress layer or intermediate layer, which is in water-permeable relationship with the said emulsion layer or into one of the processing baths for said photographic material.

The antifoggants according to the present invention can be used for any type of light-sensitive silver halide material a spectrally sensitized or non-sensitized silver halide material, a silver halide material of use in diffusion transfer processes for the production of silver images and an X-ray silver halide material. They may be used for high speed negative materials as well as for rather low speed positive materials. Various silver salts may be used as light-sensitive salt e.g. silver bromide, silver iodide, silver chloride, or mixed silver halides, e.g. silver chlorobromide or silver bromoiodide.

The silver halides are dispersed in the common hydrophilic colloids such as gelatin, casein, zein, polyvinyl alcohol, carboxymethylcellulose, alginic acid, etc., gelatin being however, favoured.

The amount of antifoggant employed in the light-sensitive silver halide material depends on the particular type of emulsion and the desired effect and can vary within very wide limits. The optimum amount of antifoggant to be added is best determined for each particular type of emulsion by trial. Generally, the most suitable concentration is between 0.2 millimole and 30 millimoles of antifoggant per mole of silver halide.

The light-sensitive emulsions may be chemically as well as optically sensitized. They may be chemically sensitized by effecting the ripening in the presence of small amounts of sulphur containing compounds such as allyl thiocyanate, allyl thiourea, sodium thiosulphate, etc. The emulsions may also be sensitized by means of reductors for instance tin compounds as described in our United Kingdom patent specification 789,823 and small amounts of noble metal compounds such as gold, platinum, palladium, iridium, ruthenium and rhodium.

Other addenda such as hardening agents, Wetting agents, plasticizers, colour couples, developing agents and optical sensitizers can be incorporated into the emulsion in the usual way.

The antifoggants according to the present invention are particularly suitable for use in conjunction with compounds Which sensitize the emulsion by development acceleration for example alkylene oxide polymers. These alkylene oxide polymers may be of various type. Various derivatives of alkylene oxides may be used to sensitize the silver halide emulsions e.g. alkylene oxide condensation products as described among others in US. patent specifications 2,531,832 and 2,533,990, in United Kingdom patent specifications 920,637, 940,051, 945,340 and 991,- 608 and in Belgian patent specification 648,710. Other compounds that sensitize the emulsion by development acceleration and that are suitable for use in combination with the antifoggants of use according to the invention are the onium derivatives of amino-N-oxides as described in Belgian patent specification 686,520.

The stabilizers according to the invention can also be used in conjunction with other known stabilizers for instance with heterocyclic nitrogen containing thioxo compounds such as benzothiazoline-Z-thione and l-phenyl- A -tetrazoline-5-thione, with mercury compounds such as those described in Belgian patent specifications 524,121, 677,337, 707,386 and 709,195 and with compounds of the 3 hydroxytriazolo-pyrimidine type (hydroxyazaindolizines) such as 5-methyl-7 hydroxy-s-triazole[l,5-a] pyrimidine.

The following examples illustrate the invention.

EXAMPLE 1 A conventional photographic gelatino silver bromoiodide emulsion (4.5 mole percent iodide) comprising per kg. an amount of. silver halide equivalent to 50 g. of silver nitrate was divided into two portions A and B. To emulsion portion B was added acetylene dicarboxylic acid diammonium salt in a concentration of 1 mmole per kg. of emulsion whereas to emulsion portion A no antifoggnt was added. Then the emulsions were coated on a conventional support and dried.

The values of speed, gradation and fog of the materials A and B formed were determined shortly after preparation and after incubation for 5 days at 57 C. and 34% relative humidity. The values given for the speed are relative values corresponding with density 0.1 above fog; the value of 100 has been given to fresh material A.

Development occurred at C. for 5 min. in a developing solution having the following composition:

Water800 ccs. p-Monomethylaminophenol sulphate-1.5 g. Sodium sulphite (anhydrous)50 g. Hydroquinone6 g.

Sodium carbonate (anhydrous)-32 g. Potassium bromide-2 g.

Water to make-1000 ccs.

TABLE Fresh material Incubated material Material Fog Gradation Speed Fog Gradation Speed $333331: 333 iii? 32 33?; i235 From these results it clearly appears that the acetylene dicarboxylic acid diammonium salt has a favourable antifogging action. ,When using instead of the acetylene dicarboxylic acid diammonium salt, the disodium salt or monopotassium salt of acetylene dicarboxylic acid, a same favourable antifogging action was observed.

EXAMPLE 2 Example 1 was repeated with the difference however that emulsion B now comprised per kg. of emulsion 2 mmole of acetylene dicarboxylic acid dianilinium salt.

The results attained are listed in the following table. The values given for the speed are relative values corresponding with density 0.1 above fog; the value of 100 has been given to the fresh material comprising no antifoggant according to the invention.

Fresh material Incubated material Material Fog Gradation Speed Fog Gradation Speed The above results show that the dianilinium salt of acetylene dicarboxylic acid has a favourable antifogging action without causing desensitization.

EXAMPLE 3 Incubated material Speed Fresh material Gradatdon Speed Fog Gradation Material Fog EXAMPLE 4 This example proves that derivatives of acetylene di carboxylic acids that are not easily dissociating and thus do not provide acetylene dicarboxylic acid anions are unsuitable for use as antifoggants in that they are completely inert and do not inhibit fog formation.

An emulsion as described in Example 1 was divided into four portions A, B, C and D. To emulsion portions B, C and D were added per kg: 2 mmole of acetylene dicarboxylic acid dimethyl ester, 2 mmole of acetylene dicarboxylic acid diisopropyl ester, and 2 mmole of acetylene dicarboxylic acid dibenzohydryl ester respectively whereas to emulsion portion A no :antifoggant was added.

The emulsions were then coated on a film support and dried.

The values of the fog produced in the materials A, B, C and D were determined shortly after preparation and after incubation for 5 days at 57 C. and 34% relative humidity. The results are listed in the table below.

Development occurred as described in Example 1.

TABLE These results show that only the dibenzohydryl ester has an antifogging action since it can provide acetylene dicarboxylic acid anions whereas the dimethyl ester and diisopropyl ester are fully inert.

The dibenzohydryl ester of acetylene dicarboxylic acid was prepared as follows.

To 500 m. of anhydrous benzene, 2 g. of p-toluene sulphonic acid monohydrate were added. The benzene was distilled off until the p-toluenesulphonic acid was dehydrated. Then, 36.8 g. (0.2 mole) of'benzohydrylalcohol and 11.4 g. (0.1 mole) of acetylene dicarboxylic acid were added and the reaction mixture refluxed for 16 hours while distilling off the azeotropic mixture of water and alcohol. The mixture was concentrated by evaporation and the dibenzohydryl ester of acetylene dicarboxylic acid obtained was recrystallized from n-hexane.

Yield: 24 g. (53%). Melting point: 79 C.

We claim:

1. Photographic material comprising a support and at least one silver halide emulsion layer containing in said emulsion layer or in a water-permeable layer coated at the same side of the support as the said emulsion layer in an amount sufficient to inhibit fogging a compound selected from the group consisting of acetylene dicarboxylic acid, a mono-or di-alkali metal salt of acetylene dicarboxylic acid, a monoor diammonium salt of dicarboxylic acid, a monoor di-organic ammonium salt of acetylene dicarboxylic acid, and a monoor diester of acetylene dicarboxylic acid which is easily dissociating and provides acetylene dicarboxylic acid anions during the processing of said photographic material.

2. Photographic material according to claim 1, wherein said compound is acetylene dicarboxylic acid.

3. Photographic material according to claim 2, wherein said compound is a rnonoor di-alkali metal salt, a

monoor di-ammonium salt or a monoor di-organic ammonium salt of acetylene dicarboxylic acid.

4. Photographic material according to claim 1, wherein said ester is a monoor dibenzohydryl ester of acetylene dicarboxylic acid.

5. Photographic material according to claim 3, wherein said di-organic ammonium salt is the dianilinium salt of acetylene dicarboxylic acid.

6. Photographic material according to claim 2, wherein said compound is added to the light-sensitive silver halide emulsion layer in an amount between 0.2 and 30 millimoles per mole of silver halide.

7. Photographic material according to claim 1, wherein said material also comprises a development accelerator of the polyoxyalkylene type.

6 8. Photographic material according to claim 1, wherein said emulsion layer is a gelatino silver halide emulsion layer.

References Cited UNITED STATES PATENTS 3,212,900 10/1965 Oguchi et a1. 96-109 2,919,985 1/1960 Dersch 96-665 10 NORMAN G. TORCHIN, Primary Examiner W. H. LOUIE, JR., Assistant Examiner US. Cl. X.R. 

